And people bleach in Asia — lightening creams and lotions are as ubiquitous in drugstores in Seoul as eye shadow. They do it in Europe, despite the restrictions there on sales of hydroquinone. You can walk into any number of black beauty salons in London and find bleaching creams and lotions.

But Africa? If you can’t be dark-skinned in Africa, then where can you?

The African-American grandmother of a friend of mine once summed up the laws that govern black identity in this country. “If you ever want to know if someone’s black or not,” she would say, “go ask their white neighbor.”

That succinct, small-town Georgia wisdom essentially outlines the rule of hypodescent, also known as the one-drop rule. The one-drop rule emerged during slavery and hardened in Reconstruction, automatically classifying as black anyone with any trace of African ancestry. It is the reason why, in the 1800s, the extremely light-skinned offspring of white fathers and black mothers were deemed slaves. It’s also the reason why, in 2011, the actress Halle Berry, who is biracial but identifies as black, became a lightning rod of controversy for maintaining that her own daughter, with white Canadian actor Gabriel Aubry, is also black.

The fact that Americans with vastly different complexions know they are black by the number of cab drivers who don’t stop for them as much as by any internal measure is a dilemma on many levels. But for Kim Tallbear, an enrolled member of South Dakota’s Sisseton-Wahpeton Oyate tribe and a UC Berkeley professor who studies race, genomics and Native American identity, the tyranny of the one-drop rule poses a specific problem in the ongoing controversy surrounding US Senate candidate Elizabeth Warren and her shifting, dubious claims of Native American identity…

…“If you want to understand Native American identity,” Tallbear said, “you need to get outside of that binary, one-drop framework. Native Americans do not fit in that binary. We have been racialized very differently in relationship to whites.”

How do we know Native Americans are racialized differently, Tallbear said? Because a white person—say, Elizabeth Warren, for example—can absorb a Native American ancestor and still maintain an identity as white. If Warren had a black ancestor, that fact would threaten her white identity…